Bc a portion of your calldown range is
, as villain we want you to have as many of those combos as possible in your range when we bluff river, so if we have them ourselves, we are blocking a portion of what we want to fold out.
i.e. when we block more of the missed draws you have more value and are folding to a jam less often overall
This is why front door draws make very poor triple barrels, and is perhaps one of the biggest "ahas" derived from solvers.